I am currently using subplots in MATLAB and this is my x tick mark data:[.4 .5 .6 .9 1.2 1.5 2 2.5 3 4 5 6 7 8 9 10 12 15 20 30 40]
I am trying to determine if there is a way to space the tick marks evenly, or expand the spacing for the lower values so you can actually read the numbers. In short I would like the physical spacing of the tick marks to be based on some predetermined constant and not the actual numerical values.
You could use logarythmic scale for x-axis - use semilogx instead of plot.(IMO this would be better in your case)
x = [.4 .5 .6 .9 1.2 1.5 2 2.5 3 4 5 6 7 8 9 10 12 15 20 30 40];
y = x/2; % some example data
figure
semilogx(x,y, '.')
set(gca,'xtick', x)
Another option is to change labels on x-ticks setting xticklabel property. Note that you can set custom values in ticks vector.
x = [.4 .5 .6 .9 1.2 1.5 2 2.5 3 4 5 6 7 8 9 10 12 15 20 30 40];
y = x/2; % some example data
ticks = [];
for t = 1:size(x,2)
ticks = [ticks t];
end
figure
plot(ticks, y, '.') % in this example same as 'plot(y)'
set(gca, 'xtick', ticks,'xticklabel', {.4 .5 .6 .9 1.2 1.5 2 2.5 3 4 5 6 7 8 9 10 12 15 20 30 40})
Related
As far as I understand the way to 3-d plot/ surface plot is "meshgrid".
But the data I have has a specific format:
X
Y
Z
1
0.1
10
1
0.2
12
1
0.3
13
2
0.1
11
2
0.2
12
2
0.3
14
3
0.1
11
3
0.2
12
3
0.3
15
The first and second column (X and Y) repeat themselves in that fashion, and I need to plot Z(X,Y).
How Do I do it?
X = 1:1:3 % grid can be set by beginning:step:end
Y = 0.1:0.1:0.3
[x,y] = meshgrid(X,Y); % then make 2d domain
% z values have to be done manually or can automate if you read your data from txt file
z = [10 12 13; 11 12 14; 11 12 15];
% and finally
surf(x,y,z)
I want to set the ticks of the colorbar to be in log scale, with simple readable ticks: 2 3 4 5 6 7 8 9 10 20 30 (and not just "10^0", "10^1");
for example I do:
x = linspace(0,0.9);
y=logspace(-1,1);
[X,Y] = meshgrid(x,y);
Z = 220 *sqrt((1-X).*Y); %just random function(x,y)
[M,c]= contourf(X,Y,Z,100);
c.LineColor = 'none';
set(gca,'ColorScale','log')
cl=colorbar;
ylabel(cl, 'color')
cl.Ticks=[ 2 3 4 5 6 7 8 9 10 20 30];
cl.TickLabels = num2cell([ 2 3 4 5 6 7 8 9 10 20 30]);
It doesn't work that way. How to do it?
Your code works well and as expected. If you check your colorbar, the lower limit value is 22, and therefore you only see the last label.
x = linspace(0,0.9);
y=logspace(-1,1);
[X,Y] = meshgrid(x,y);
Z = 220 *sqrt((1-X).*Y); %just random function(x,y)
[M,c]= contourf(X,Y,Z,100);
c.LineColor = 'none';
set(gca,'ColorScale','log')
cl=colorbar;
ylabel(cl, 'color')
cl.Limits=[2 cl.Limits(2)] % change the range
cl.Ticks=[ 2 3 4 5 6 7 8 9 10 20 30];
cl.TickLabels = num2cell([ 2 3 4 5 6 7 8 9 10 20 30]);
d=[1 2 3 4;5 6 7 8;9 10 11 12;13 14 15 16]
bar_widh=0.2;
figure;
h = bar(d,bar_widh);
for i=1:2:4
for j=1:4
x=d(i,j)
y=d(i+1,j)
figure,plot(x,y);
end
i=i+1;
end
In this code I had plotted a bar chart and I want to extract values from bar chart. (Values are correctly extracted but only one point is plotted; not a line) But i'm getting wrong results.
My aim is to plot a line between
d(1,1) and d(2,1);d(3,1) and d(4,1);
d(1,2) and d(2,2);d(3,2) and d(4,2);
d(1,3) and d(2,3);d(3,3) and d(4,3);
d(1,4) and d(2,4);d(3,4) and d(4,4);
In first figure I need 2 lines(from 1 column); in second figure I need 2 lines(from 2 column); in third figure I need 2 lines(from 3 column) and in fourth figure I need 2 lines(from 4 column).
no.of figures=no.of columns
Version 2
I tried another version
d=[1 2 3 4;5 6 7 8;9 10 11 12;13 14 15 16]
bar_widh=0.2;
figure;
h = bar(d,bar_widh);
saveas(h,'testfigure.fig');
clear
close all
h=hgload('testfigure.fig');
ch=get(h,'Children');
l=get(ch,'Children');
x=get(l,'Xdata');
y=get(l,'Ydata');
and i'm getting error as
Error using get
Conversion to double from cell is not possible.
Error in Untitled5 (line 10)
l=get(ch,'Children');
d=[1 2 3 4;5 6 7 8;9 10 11 12;13 14 15 16];
bar_widh=0.2;
figure;
h = bar(d,bar_widh);
figure; hold on;
for i = 1:size(d,2)
x = [d(1,i) d(2,i)];
y = [d(3,i) d(4,i)];
plot(x,y);
end
To plot a line, you must make sure the parameters x and y in plot(x,y) are vectors than scalars. For example, to plot a line between P1 = [P1x, P1y] and P2 = [P2x, P2y], the paramenters should be:
x = [P1x, P2x]; y = [P1y, P2y];
As in this link, I have:
| 0.1 0.2 0.3 0.4
----------------------
1 | 10 11 12 13
2 | 11 12 13 14
3 | 12 13 14 15
4 | 13 14 15 16
Y = [0.1 0.2 0.3 0.4];
X = [1 2 3 4];
Z = [10 11 12 13; 11 12 13 14; 12 13 14 15; 13 14 15 16];
I plotted the surface Z using the command "surf(X,Y,Z)" in matlab. I got:
But really I don't understand the plotted surface. Can someone explain to me in details (in a text) what happens in this surface? For example: how can we observe the point (2,0.2,12)?
Include some labels and a colorbar and everything should be clear:
Y = [0.1 0.2 0.3 0.4];
X = [1 2 3 4];
Z = [10 11 12 13; 11 12 13 14; 12 13 14 15; 13 14 15 16];
surf(X,Y,Z)
colorbar
xlabel('X')
ylabel('Y')
zlabel('Z')
As suggested in the comments you can find your point on the surface by adding:
hold on;
plot3(2,0.2,12,'ro','MarkerSize',10,'MarkerFaceColor','r');
it then appears as a red dot.
Your table contains 16 points, these are plotted and the area inbetween, colored according to the applied colormap with the lowest z-value of the group of 4, which is according to the doc the surface height.
Actually it would be cleaner coding if you'd include the following line before the plot:
[X,Y] = meshgrid(X,Y);
this way all your input variables get the same dimensions:
X =
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
Y =
0.1 0.1 0.1 0.1
0.2 0.2 0.2 0.2
0.3 0.3 0.3 0.3
0.4 0.4 0.4 0.4
Z =
10 11 12 13
11 12 13 14
12 13 14 15
13 14 15 16
In case of surf the function does that for you, but other plotting functions are may not that tolerant.
I need to simple plot B vs. A as bar plot in MATLAB, but I don't want my x axis showing completely from 1 to 274. I only need to show the existing data point on my x axis, which can be done easily in Excel as in the image below. How can MATLAB do this?
A=[1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 18 20 25 27 29 37 40 42 43 48 73 204 242 274];
B=[30 15 5 9 5 6 3 3 2 1 4 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1];
You need to set both 'XTick' and 'XTickLabel' axes properties:
bar(B);
set(gca,'XTickLabel',A)
set(gca,'XTick',1:numel(A));
xlim([0 numel(A)+1]);
Here is an inelegant, but, nonetheless, working solution to your question:
x = [1,4, 6, 7]; % Your data
uni = unique(x)
yMax = length(find(x == mode(x))) + 1;
c = cell(1, length(uni));
c = strread(num2str(uni),'%s')
hist(1:length(uni));
axis([0 length(uni) 0 yMax])
set(gca, 'XTick', 1:length(uni));
set(gca, 'XTickLabel', c);
Basically, this plots the histogram as if the data were spread from 1 to the number of unique elements. Then, it sets the tick marks at each histogram value. Then, it labels each tick mark with the correct number.